Two parallel traditions of clinical work and developmental research have highlighted the importance of play as an indicator of adequacy of functioning. Children's play reveals their cognitive and affective status. In addition, mother-child play reveals the adequacy of functioning of that dyad. Play therefore is a particularly valuable context in which to study the effects of mothers' affective disorders on their children. The present study regards three related topics 1) the effects of maternal affective disorder (and chronicity of that disorder) upon symbolic complexity and affective aspects of children's play e.g., issues of nurturance or aggression; 2) the effects of maternal affective disorder on dyadic functioning in play -- for example, the extent to which she imposes her own agenda, and the ability of the dyad to sustain play; and 3) the relation between the dyadic variables and the child play variables, controlling for maternal diagnosis. Participants are 2- to 4-year-olds and their mothers who have been videotaped in semi-naturalistic conditions representative of early rearing experiences. Mothers have been diagnosed as normal or as depressed (bipolar, unipolar, minor depression).